Services: Pump Stations

Tata & Howard provided engineering services for design, bidding, construction administration, and resident observation to Aquarion Water Company for improvements to their existing Hemlocks Raw Water Pumping Station in Fairfield, CT. The project included refurbishing five 300 hp centrifugal pumps and motors, replacing the existing variable frequency drives (VFDs), installing new piping, check valves, and strainers for each pump.

As this facility is a source of supply for Aquarion’s Main System, it needed to be kept operational throughout the construction. The sequence of work required a single pump to be taken off line; refurbished; reinstalled with new piping, VFD, and appurtenances; tested and placed back into service prior to the next pump being taken off line.

AFTER improvements to the Hemlocks Pumping Station.

Another important aspect of the project was to replace the existing strainers so that they were easier for the plant operators to clean as they get clogged with eels. To simplify maintenance, new stainless steel wye strainers with bottom access to the screens were installed on the suction side of each pump.

Tata & Howard is providing engineering services to the Grafton Water District for the Trinity Avenue Pump Station at the Trinity Avenue Wellfield. The project included permitting, design, and bidding of the pump station as well as providing assistance with permitting, design, and reporting to the Massachusetts Department of Environmental Protection (MassDEP) for the proposed Trinity Avenue Well site. The property was owned by the Massachusetts Division of Fisheries and Wildlife (DFW). The Grafton Water District swapped land with the DFW to obtain ownership and control of the Trinity Avenue site. Test wells were installed and short term pump tests were completed on each of the wells. Based on the results of the tests, it was recommended to install a three well configuration of 18 inch x 12 inch gravel packed wells resulting in approximately 800 gallons per minute (gpm). The project included an evaluation of alternatives for the access road including installation of a bridge or an open bottomed culvert, and T&H assisted with the preparation of permanent easements for the installation of utilities and roadway to the well site. In addition, T&H prepared and submitted an NOI to the Grafton Conservation Commission. Design included double wythe block and interior concrete painted block with wood truss roof and asphaltic shingles; and security included chain link fence, gates, locks, intrusion alarms, and lighting. T&H also assisted with the coordination of the installation of three phase power to site. Chemical feed at the station includes KOH for pH adjustment and chlorine gas for disinfection. Standby power was included in an outdoor enclosure. The design also included a 24-inch transmission main for 4-log removal. Currently, T&H is providing construction administration and resident observation services.

The Towns of Canaan, Vermont and Stewartstown, New Hampshire operate a shared wastewater treatment facility, which required significant upgrades. The existing facilities were 40 years old and although a few upgrades were performed in the 90s, the facilities were not performing well, did not meet Life Safety codes, and required significant maintenance. The upgrade met all of the goals of the Client by providing for simple operation and maintenance requirements, meeting the Life Safety codes, eliminating confined spaces, lowering of electrical power costs, and meeting discharge parameters through production of high quality effluent. The solutions developed for the upgrade to this facility were also economical.

Control building insulated concrete forms

One of the primary elements of the design was the consideration of the economics of energy reduction. The design incorporated insulated concrete form construction for the building walls with R-49 insulation rating in the ceilings. The design also included a wood pellet boiler with a pellet silo and hot water heating system, which allowed for reduction of explosion proof heaters in the headworks building. All of the windows were low-E and highly insulated, and an outer glassed-in entry way increased the solar gain retention of the building and reduced heat loss. The process headworks and operations buildings were constructed as single story structures, increasing operator safety. The lagoon aeration system is now a fine bubble, highly efficient process with additional mixing provided by solar powered mixers that help reduce aeration requirements, improve treatment, and allows for the addition of septage, all at no cost due to solar power. The pump station upgrades were designed to eliminate daily confined space entry by the operator by the conversion to submersible pumps. For sludge removal, a unique and simple “Sludge Sled” system was incorporated, which allows the operators to easily remove the sludge at their convenience. Sludge treatment is accomplished with a geo-bag system that allows the sludge to be freeze dried, reducing the volume by almost 50% with no energy consumption. The influent pump station was designed with three pumps instead of the normal two-pump system in order to meet both present and future design flows, allow for lower horsepower pumps, improve flexibility, reduce replacement costs, and reduce energy costs. The other four deep dry pit pump stations were converted to wet wells and submersible pumps, eliminating confined spaces, and are equipped with emergency generators, eliminating the need for operator attention when power is lost.

Solar mixers for lagoons

The incorporation of highly energy efficient building components resulted in reducing annual operation and maintenance costs, which resulted in lower user rates and a more sustainable facility. All building components are virtually maintenance free. All of the equipment and processes were selected to reduce both annual and future replacement costs.

The treatment system is a 3-cell aerated lagoon system, and the solar powered mixers were installed to enable reduction of the aeration needs and horsepower during the summer months when septage is added. The aeration blowers, which are housed in insulated enclosures, reduce noise and were sized to allow for the addition of septage to the lagoons, which is not common in Vermont. The aeration blowers are controlled with Variable Frequency Drives (VFDs), which allow for greater operator control of aeration and provide energy cost savings. The operation is simple and safe for operators and others who need to maintain the facility and equipment. The design has provided flexibility to the operators and has resulted in an energy efficient, sustainable solution for this community.

Tata & Howard provided engineering services for permitting, design, and bidding of the 1.3 mgd chemical injection Trinity Avenue Pump Station at the Trinity Avenue Wellfield. The project included an evaluation of alternatives for the access road including installation of a bridge or an open bottomed culvert; assistance with the preparation of permanent easements for the installation of utilities and roadway to the well site; preparation and submittal of an NOI to the Grafton Conservation Commission. The design included an access road, bailey bridge with abutments, double wythe block building, interior concrete painted block with wood truss roof and asphaltic shingles, installation of three (3) submersible pumps and pitless adaptors, approximately 1,800 linear feet of 6-inch and 12-inch water main, emergency liquid propane tanks and generator, instrumentation and controls, a SCADA system for the pump station and wells, and a 24-inch transmission main for 4-log removal. Security included chain link fence, gates, locks, intrusion alarms, and lighting. Tata & Howard also assisted Owner with the coordination of the installation of three phase power to site. Chemical feed at the station includes KOH for pH adjustment and chlorine gas for disinfection. Standby power was included in an outdoor enclosure. The project is currently under construction and is expected to be completed by the end of 2017.

Tata & Howard designed and constructed the improvements to eliminate low and inadequate system pressures, construct a new source, pilot test filtration for manganese removal, design and construct required distribution system piping to connect the plant and storage tank with the system, design a new concrete storage tank, booster pump stations, and the filtration facility for manganese removal. The project was very successful and remains in great condition today.

Tata & Howard assisted Maine Water Company with mechanical, structural, and architectural design of a new high service zone booster pump station on Barra Road within the Biddeford-Saco water distribution system. The new pump station replaced the existing Alfred Road station, providing pumping capacity to meet current demands in a majority of the City of Biddeford as well as room for future expansion. Funding for the project was provided in part by the Maine Drinking Water Program State Revolving Fund (DWSRF).

Mechanical design for the project consisted of sizing and selection of three (3) centrifugal booster pumps, associated piping, and appurtenances. The pumps were sized with input from a hydraulic model of the system developed by Tata & Howard, and they were selected to maximize the available flow from a 16” cast iron pipe line that crosses the Maine Turnpike from the water system’s major storage reservoir. A pipe gallery was incorporated into the slab and foundation design as well as insulated concrete form (ICF) foundation walls. Per the Owner’s request, the architectural design used colors and materials similar to the other buildings within the surrounding commercial office park. Also, a gable roof canopy was added to the design (pictured below) to help shield the emergency backup generator from the elements. Precautions were taken to ensure proper air flow and ventilation was achieved to meet the requirements of the generator. Construction of the pump station was completed in 2015.

Wastewater treatment facility that serves the Towns of Canaan, VT and Stewartstown, NH

CLIENT: The Towns of Canaan, VT and Stewartstown, NH

PROJECT: Shared Wastewater Treatment Facility

THE CHALLENGE: The existing wastewater treatment facility was 40 years old, costly to operate, and did not meet state and federal water quality standards. In addition, the Towns had very limited funds with which to upgrade the treatment facility.

THE SOLUTION: Tata & Howard helped the Towns secure a $2.412 million low-interest, long-term loan and $1.69 million in grant funds from the U.S. Department of Agriculture (USDA) Rural Development in order to build the new facility.

Tata & Howard, Inc. provided complete consulting engineering services for the construction of the wastewater treatment facility project which included the complete upgrade of four pump stations as well as the upgraded 0.185 mgd, 3-cell lagoon wastewater treatment facility. In addition, Tata & Howard’s St. Johnsbury, Vermont office, formerly Leach Engineering Consultants, provided full design services for all of the upgrades. The Towns now enjoy a state-of-the-art, reliable wastewater treatment facility that meets the Effluent Discharge limits to the Connecticut River and provides for a more efficient treatment process. The new influent screening and grit removal processes extend the life of the treatment facility components. In addition, septage receiving provides for additional income and also provides service to the residents of the Towns that are not on public sewer. The design included numerous energy-efficient features such as variable-frequency drives (VFDs) on aeration blowers, solar-powered lagoon mixers, a wood pellet boiler for heat, energy-efficient windows, and insulated concrete form (ICF) walls, resulting in a reduction in annual operation and maintenance costs. The pump stations were upgraded to eliminate operators entering below grade structures and to allow for future pump replacement that would be lower cost with it would be with the original centrifugal pumps.

PROGRESS: The project is complete, and the Towns celebrated the completion of their shared $4.12 million wastewater treatment facility with a ribbon-cutting ceremony in Canaan, VT.

PROJECT: Mountainaire asset management based water distribution system study to assist with prioritizing water system improvements

THE CHALLENGE: Mountainaire is a small water distribution system with limited manpower and revenue resources, and the operation and maintenance of the system is often reactive rather than proactive.

THE SOLUTION:We successfully helped secure WIFA funding for the completion of the study which provides guidance to the PUC on how the system operates, what improvements are needed for efficient operation and continued maintenance of the system, and a prioritized approach to assist in funding and implementation of projects. This asset management based water distribution system study addresses undersized deteriorating water mains, above grade assets, and the energy efficiency of the pumping system. The study evaluates the system as a whole, based on above grade and below grade assets. Above grade assets are evaluated based on remaining useful life expectancy. Water mains are based on hydraulic capacity, criticality, and risk of failure. A hydraulic model was created for the study.

PROGRESS: Using the findings of the study, we are currently providing engineering services to evaluate flow and pressure requirements for the existing Kiowa Site booster pump station in order to construct a constant pressure pumping system to replace the existing booster pump and hydropnematic tank system that is old and failing.

THE CHALLENGE: The sites were very small and restricted with high groundwater levels, and there were adjacent wetlands and private property. All three buildings were also very small and had other issues such as asbestos.

An existing building is inspected during the design phase

THE SOLUTION: We determined that the best course of action would be to demolish the buildings and convert the concrete dry pit that housed the pumping equipment into a wetwell for new, submersible pumps. The solution saved the Town hundreds of thousands of dollars.

PROGRESS: Tata & Howard provided the project design and will be putting the project out to bid this summer. We will also provide construction administration when construction begins in the fall.

THE CHALLENGE: More stringent USEPA and MassDEP regulations, including Stage 2 Disinfectants/Disinfection-by-Product Rule (S2 D/DBPR) and the Long Term 2 Enhanced Surface Water Treatment Rule (LT2ESWTR), resulted in the Town of Falmouth needing to make a decision on whether to construct a filtration facility in compliance with the SWTR or to upgrade disinfection processes only at the existing Long Pond Water Treatment Facility (LPWTF) to maintain the existing Filtration Waiver.

THE SOLUTION: Because the existing LPWTF utilized no filtration to remove bacteria, organics, and particulates, the water quality entering the distribution system was an ongoing concern with elevated turbidity and organics leading to seasonal color, taste, and odor complaints; elevated bacteria and concentrations; and elevated algae counts. In addition, the high doses of chlorine needed to maintain the disinfection residuals required for an unfiltered supply reacted with the organics in the raw water to form disinfection by-products. Therefore, the only viable option for the Town of Falmouth was a new water treatment plant. After evaluating 22 treatment processes and developing eight treatment alternatives for pilot testing, only one treatment process met all goals: Dissolved Air Flotation (DAF) clarification, intermediate ozone followed by filtration. This alternative also scored favorably on the benefit/cost analysis.

Tata & Howard provided design and construction services for the new Dissolved Air Flotation (DAF) facility with a design capacity of 8.4 million gallons per day (mgd) for the Long Pond surface water supply for the Town of Falmouth, MA. The water treatment plant (WTP) utilizes coagulation, mixing, flocculation, dissolved air flotation (DAF), dual media filtration including granular activated carbon (GAC) above sand, chemical feed systems, and an intermediate ozone feed. Building components include HVAC, plumbing, fire sprinkler, gas and electrical services. Other work included site work with exterior piping systems, exterior above and below ground tanks, sludge holding lagoons, construction of a garage, new raw water intake and pump station, directional drilling of raw water mains, and demolition of equipment and site piping at the existing water treatment facility.

As part of the project, Tata & Howard provided design and permitting of a new 8.4 mgd intake and raw water pump station (RWPS) for the WTP. The new intake and RWPS were constructed along the eastern shore of Long Pond and replaces the existing intake and Low Lift Pump Station. The new intake and RWPS includes a two-level intake consisting of two 8.4 mgd rated intake screens installed at elevations -3 feet below mean sea level (MSL) and -13 feet below MSL. The 36-inch HDPE intake pipeline connects the intake screens to the new RWPS located approximately 150 feet from the eastern shore of Long Pond. An air burst system was designed in the RWPS to provide a means for routine cleaning of the new intake screens.

An accelerated 11 month design and permitting schedule, followed by contractor prequalification, bidding, and award, were completed in time to qualify the Town for >$3M in principal forgiveness.

The construction of the Long Pond Water Treatment Plant progressed on schedule and was completed in 2017. The plant included numerous sustainability and energy efficiency initiatives including the following:

Recycling spent backwash water to head of plant and back into the treatment process, after it passes through a plate settler to remove solids.

The plant went online on October 18, 2017. The work was funded under the SRF program. The Long Pond Water Treatment Plant received an ENR New England 2017 Best Project Award in the Water/Environment category, and an Associated Builders & Contractors of Massachusetts Eagle Award in the Public Works – Environmental category. For a drone video of the new water treatment plant taken by the general contractor, Methuen Construction, please see below: